Most portable, handheld, lead-acid battery test instruments fall into two categories—conductance testers and micro-load testers. Conductance testers do not apply significant loads to the battery under test. Micro-load testers employ relatively small loads, e.g., on the order of 15-40 amperes, to gauge the battery's condition and status based on the battery's response to, and recovery from, the load. However, several incipient battery problems, such as internal shorts, cannot be readily detected without applying very heavy loads, e.g., on the order of 160 amperes, for several periods of ten or more seconds.
Presently, it is believed that portable battery test instruments do not apply significant battery load testing or charging analysis. While moderate-load battery testers (e.g., 100 A) are presently available, these devices are, generally, simple voltmeters that do not perform an analysis of the battery's condition. These moderate-load testers are also limited to providing a short-term application of the load, typically less than 10 seconds due to rapid heating, and are, generally, of a single, fixed load, i.e., non-configurable. Due to the size of the resistance elements employed within, and the heat generated by, heavy-load testers, these large devices have typically been confined to console-style units or heavy wheeled cabinets used in garages and repair shops. A portable, heavy-load battery tester would be of great benefit and application in many vehicle test and repair scenarios, particularly those involving heavy equipment or large trucks. Additionally, a portable heavy load battery tester would be much easier for a technician to carry to the vehicle, instead of maneuvering a traditional heavy console unit into close proximity to the battery. Field service operations would also benefit from a small, portable heavy load batter tester; this device could be carried to heavy construction equipment located on a job site. Configurability of the load, coupled with a modular format, is also desirable.